25W power amplifier circuit TDA1521A with the least peripheral components

The power amplifier circuit made of high-fidelity power amplifier IC TDA1521A has the characteristics of few peripheral components, no need for debugging, and it works as soon as it is installed. It is suitable for self-made, used for power connection of walkman, or for modifying low-end computer active speakers.

TDA1521A adopts a nine-pin single-in-line plastic package, which has the characteristics of high output power, small gain difference between the two channels, no impact sound when the speaker is turned on and off, and reliable overheat, overload and short-circuit protection. TDA1521A can be powered by both positive and negative power supplies, as well as single power supplies. The circuit principles are shown in Figures 1(a) and (b) respectively (click here to download the schematic diagram). When powered by dual power supplies, two audio output capacitors can be omitted, and the sound quality of high and low bass is better. When powered by a single power supply, the power filter capacitor should be as close to the power supply end of the integrated circuit as possible to avoid self-excitation inside the circuit. When making, the integrated block must be equipped with a heat sink before it can be powered on for sound testing, otherwise the integrated block is easily damaged. The heat sink cannot be less than 200×100×2mm3.